Air Quality in Indiana

This is the seventh article in a series about air quality in general and how it applies to Indiana. I am planning to publish an article every two weeks to cover air pollution topics. From time to time, I will include articles written by guest columnists. This article is by Scott Deloney, branch chief for the Air Programs Branch in IDEM’s Office of Air Quality. Scott has many years of experience in air quality issues, including outreach for officials and residents in communities across the state. In this article, Scott provides information about air quality forecasting and advisories that are issued.

IDEM issues daily air quality forecasts for seven forecast regions that cover all ninety-two counties in Indiana. These forecasts predict the concentrations of ozone and fine particles likely to be in the ambient air. When pollutant concentrations are predicted to exceed the limits set by the United States Environmental Protection Agency (U.S. EPA) to protect human health, Indiana will issue an Air Quality Action Day (AQAD). This is a notice to the public that the potential for elevated pollutant concentrations exists for the next day. The air quality forecasts prepared by IDEM are based on current weather and measured pollutant concentrations, the predicted weather for the next day, and anticipated pollution that may be carried by winds to Indiana from other states. IDEM air quality forecasters rely in part on computer models that use weather conditions and other factors to predict air quality concentrations throughout the country.

To assist in communicating potential health effects associated with exposure to air pollutants, U.S. EPA developed a tool called the Air Quality Index (AQI). The AQI consists of six color-coded ranges of varying air quality levels that health studies have shown can affect a person’s health. The AQI ranges include:

Good (coded green): No health effects for all groups of people.

Moderate (coded yellow): Acceptable air quality to breathe without major health effects for all groups of people.

Unhealthy (coded red): Air quality may cause all people to begin to experience health effects.

Very unhealthy (coded purple): Air quality will likely cause the entire population to experience health effects.

Hazardous (coded maroon): Air quality will cause the entire population to experience adverse health effects.

Air quality monitors measure the actual pollutant concentrations. When concentrations are predicted to exceed U.S. EPA’s National Ambient Air Quality Standards for ozone (8-hour average concentration of 76 parts per billion or higher) or fine particles, PM2.5, (24-hour average concentration of 35 micrograms per cubic meter of air), an Air Quality Action Day is declared. This means the potential for harmful air quality exists and everyone should avoid prolonged outdoor exposure to prevent or minimize potential adverse health effects. An Air Quality Action Day also alerts people to take steps to reduce emissions into the air to help lower pollutant concentrations. Email alerts of Air Quality Action Days, air quality forecasts for the entire state as well as air quality monitoring information can be found on the IDEM SmogWatch website. Air quality forecasts for the entire country can be found at the U.S. EPA AIRNow website.

The determination of whether an Air Quality Action Day alert is or is not issued, is based on a prediction very similar to a weather forecast. If predicted weather conditions change unexpectedly, the actual measured pollutant concentrations may be lower or higher than forecasted. Additionally, a measured exceedance of the standard may not occur on days that Air Quality Action Days are issued. This is part due to the actions that businesses and citizens take on Air Quality Action Days to reduce emissions that lead to elevated pollutant concentrations.

Indiana’s air quality is influenced largely by the way we go about our day-to-day activities. Routine tasks like making a deposit at the drive-through bank, or driving alone can affect air quality. Cars and trucks contribute up to half of the emissions that create air pollution. Even the way we perform household chores matters. Running electrical appliances needlessly uses more power, and producing that energy can also result in additional air pollution. Therefore, when IDEM issues an Air Quality Action Day, the agency also recommends that Hoosiers do their part to help mitigate air pollution. Steps that can be taken to help include:

Walk, bike, carpool or use public transportation.

Avoid using the drive-through and combine errands into one trip.

Avoid using gasoline-powered lawn equipment until after 7:00 PM.

Turn off your engine when idling for more than 30 seconds.

Conserve energy by turning off lights or setting the air conditioner to 75 degrees or above.

When an Air Quality Action Day is issued, together, six million Hoosiers can make a positive difference to improve air quality.